Mexican federal police have been stopping some minibuses and removing people from the caravan of Central American migrants, even though they had paid fares.

Associated Press journalists saw about a half dozen of the small buses pulled over at a spot near the town of Escuintla in Chiapas where police blocked the road with their cars on Wednesday. A column of other migrants on foot trekked past.

Such buses are common intercity transport in the region.

Driver Johnny Morales Castellanos said officers told him to remove the migrants because "the insurance doesn't cover them because they're foreigners."

The migrants weren't detained, but had to continue the day's planned 45-miles (75-kilometer) trek on foot in 90 degree heat — at least unless they can find another ride.

It's not immediately clear if the move is part of a broader effort to restrict the caravan's progress.

Children appear to make up only about 5 to 10 percent of migrants in a caravan traveling through far-southern Mexico. But parents' hopes for their future and fears of what could happen to them back home are clearly a motivating factor behind many people's decision to leave.

Ludin Giron is a street vendor from Choloma, Honduras. She was riding in a motorcycle taxi designed for two with her three children, as well as another mother and her daughter.

Giron held son Justin in her lap, helped by daughter Astrid, 5. Behind them sat Nicole, 3. She described the threats and pressure they would be likely to face back home once they're older.